The instant application should be granted the priority date of Dec. 30, 2010, the filing date of the International patent application PCT/EP2010/007991.
The invention relates to longwall equipment for mechanical extraction in longwall mining, in particular in underground coal mining, with a face conveyor disposed along the coal face, an extraction machine displaceable along the face conveyor and having shield support units fitted to the face conveyor at an angle thereto.
Longwall equipment with the aforementioned features and a method for controlling such longwall equipment are described in WO 2009/103303. In this regard, it is set out in detail in the aforementioned publication that the automation of such a control of longwall equipment is generally dependent on a knowledge of the position of the longwall equipment and its elements in the space, but in particular a knowledge of the height of the face opening existing in each case in the region of the forward end of the top canopy. The determination of the concerned basic values for the calculation of, for example, the face opening height takes place, according to the prior art, via inclination sensors fitted to the main components of the individual shield support units such as floor skids, gob shield, supporting connection rods and top canopy, by means of which sensors the inclination of the respective components with respect to the horizontal is ascertained. By comparing the recorded data with basic data stored in an evaluation unit and defining the geometrical orientation of the components and their movement during advancing, it is possible to calculate the given height perpendicular to the bed of the shield support unit at the forward end of the top canopy, which represents a measure for the height of the face opening.
The known approach is associated with the drawback of costly calculation work, which also requires appropriate acquisition of the basic data applying to the given design of the shield support unit used and the preparation of an applicable algorithm for the calculation of the height perpendicular to the bed.
Apart, from the aforementioned indirect determination of height data, a direct acquisition of height data by means of a hydrostatic tube balance system during the advancing of tunnels is known from DE 43 33 032 C2. Here, there is disposed between the tunnel advancing machine and a reference point a hydrostatic tube balance system, the closed, liquid-filled tube whereof is assigned with one end to the reference height and with the other end to the determination of other magnitudes of the measurement height of the tunnel advancing machine.
The problem underlying the invention is to simplify the determination of height data with generic longwall equipment.